DESCRIPTION: (Verbatim from the Applicant's Abstract) The primary objective of this proposal is to study the neuroanatomical and biochemical substrates of Late-Onset Minor Depression presenting at general medical/geriatric clinical settings. We also propose to examine the role of medical comorbidity, together with structural abnormalities, in the pathophysiology of minor depression. In this study, we will focus exclusively on the frontal lobes and obtain volumetric estimates of its subregions together with quantitative estimates of high intensity lesion volume using magnetic resonance imaging (MRI). We will also examine biochemical measures such as N-Acetyl Aspartate, Choline and Creatine from the gray and white matter of the frontal lobes using magnetic resonance spectroscopy (MRS). The relationship between specific neuroanatomical measures and relevant clinical indicators of disease burden will be studies and their relative contributions to late onset minor depression ascertained.